FRANKLIN, La. — Deep in the swamplands of Louisiana, out of a clearing in the dense foliage that covers this coastal stretch, the roar of jet engines echoes across the landscape.
It is the sound of military aircraft — an escalating hum that evokes images of acceleration, takeoff and things on the move.
But these engines — which once transported troops in Iraq and Afghanistan — now move water. Millions of gallons of water.
They are a part of what two Louisiana companies believe will be the next step in the high-powered, fuel-intensive business of hydraulic fracturing — the technique that has created an American oil and gas boom.
Using retired military helicopter engines, Green Field Energy Services and Turbine Power Technology are building pressure pump systems that are key to that most important service in modern oil and gas drilling while doing what no competing pumps can: Run completely on low-cost natural gas.
Their products have added to an intensifying engineering race among several companies vying to offer oil field machines that can use natural gas instead of diesel.
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The key to the effort lies at the heart of the companies’ Louisiana plant, where stacks of green, steel canisters hold powerful battlefield engines that came from the mountains of Afghanistan and deserts of Iraq to this land of alligators and shrimp boats on the nation’s southern edge.
The turbine engines — compact cylindrical packages of high-grade steel — once powered massive Chinook and Huey helicopters. But in a flourish of innovation, Turbine Power Technology has turned the old engines, formerly destined for scrap, into oil field machines.
“We basically take one man’s junk and turn it into treasure,” said Ted McIntyre, CEO of Turbine Power Technology, an engine company that he co-owns with Green Field Energy Services.
A team that includes more than a dozen military veterans works at the Louisiana plant to restore the worn engines. Some tinker with the delicate steel blades that help move air through the turbines at hundreds of miles per hour to generate power. They also tweak the machines so that they can burn diesel and natural gas, in addition to jet fuel.
Others in the plant load the engines into large, orange frames and configure them to drive pumps that can blast millions of gallons of water, sand and chemicals into underground rocks to free up oil and gas.
The novel use of turbines has drawn the interest of industry players including Shell, Apache Corp. and GE, each of which has partnered with Green Field or used its services. It also has turned heads at engine manufacturing icon Caterpillar, which makes both conventional diesel engines and turbines for other uses.
That’s because the shale boom has made natural gas a bargain fuel, and companies believe using it instead of diesel can cut fuel costs by more than 30 percent.
Switching fuels could mean huge savings for oil and gas businesses, which in 2012 used more than 700 million gallons of diesel for hydraulic fracturing, at a cost of around $2.38 billion, Apache estimates. Using natural gas in general would have reduced that cost.
But if companies had used field gas, burning natural gas tapped directly from wells instead of processing and trucking it to drilling sites, Apache estimated they would have cut fuel costs by 70 percent — about $1.67 billion industrywide.
The turbine-powered pumps that Green Field operates for oil companies can help make that happen, said Mike Bahorich, Apache’s executive vice president of technology, which has tested Green Field’s pressure pumps but hasn’t used the system for fracturing.
“We are extremely impressed,” Bahorich said.
Other companies have converted high-horsepower engines to run on a combination of natural gas and diesel, but only Green Field has done a fracturing job using liquefied natural gas alone.
Green Field says the turbines it uses are also flexible.
“On Monday, you can put diesel in it,” Green Field CEO Mike Moreno said. “If you run out of diesel and all of a sudden an LNG truck shows up, on Tuesday you can run on LNG.”
So far, Green Field’s pump assemblies have been active in some major shale plays, including the Eagle Ford and Permian Basin in Texas; the Haynesville, which lies under East Texas, Arkansas and Louisiana; and the Marcellus in the northeastern United States.
Its engines are smaller than comparable diesel setups of similar power, meaning that they can reduce the physical footprint of a well pad, Moreno said. And natural gas engines emit less of the greenhouse gas carbon dioxide than diesels.
Evolution Well Services, based in Calgary, Alberta, is the only other company now using turbines in the oil field. It uses a different approach in which a turbine powers multiple electric pumps.
The emergence of Green Field and other companies looking to burn more natural gas in hydraulic fracturing has inspired a rush of innovation, even among manufacturers of engines that have long relied on diesel.
“It’s pretty exciting for us,” said Diana Hopkins, a product definition engineer for Caterpillar, which plans to offer “dynamic gas blending engines” for fracturing this summer. The engines burn natural gas and diesel at the same time.
Though Caterpillar has the capability to produce turbines like those used by Green Field, the company is focused on modifying its popular diesel engines to use more natural gas, Hopkins said.
While turbines have the advantage of being able to run entirely on natural gas, they require higher quality metals that make them more expensive than other engines, which is why Green Field has turned to retired turbines. Turbines also burn more fuel than conventional diesel engines to produce the same amount of power, but with the low cost of natural gas they are still able to provide fuel cost savings and emissions benefits.
“We think there is a place for turbines,” Hopkins said. But Caterpillar believes the efficiency and cost advantages of diesel engines continue to make them attractive, she said.
Green Field and Turbine Power Technology, meanwhile, may face some limitations based on their supply of engines. They have a stock of about 200 that they gradually are refurbishing and deploying. But to ensure a future beyond retired military engines, Turbine Power Technology plans to begin manufacturing an adapted version of the helicopter engines, based on a licensed design from manufacturer Honeywell, McIntyre said.
He would not detail the prices he paid for used engines, but said that the new engines the company manufactures will not have to use the same high-quality materials needed for new aircraft turbines, which can cost as much as $1.8 million each. That means Turbine Power Technology’s new turbines won’t drive up Green Field’s fracturing rates higher than competitors using conventional diesel engines, McIntyre said.
If Green Field even gets to the point of an engine shortage, “that will be a very high quality problem to have,” said Evan Templeton, managing director for leverage finance research for the investment bank Jeffries. Templeton researched Green Field before Jeffries helped raise $250 million in financing for the company.
For now, Green Field is hoping its capability to use all natural gas will help it gain ground.
“This certainly has the potential to change the industry,” Moreno said.
And the fracturing business isn’t Green Field’s only target, Moreno said. The company is producing generators for the oil field and is interested in dethroning diesel elsewhere.
“Anywhere there’s a diesel engine, we should have a shot at replacing it,” Moreno said.